It is commonly known in the computer industry that the current generation of P5 type microprocessor chips, such as Intel Corporation's Pentium Processor, generate a significant amount of heat during operation. If the heat generated by the processor is not properly dissipated, then the heat builds up and raises the temperature of the microprocessor chip beyond its maximum recommended operating temperature, thereby adversely affecting the performance of the processor. The build up of heat will continue to be a problem in newer generations of microprocessor chips since, as the number of transistors being incorporated into each new processor design continues to increase, the amount of heat generated by the operation of these newer chips will also tend to increase.
Since an excessive amount of heat build up adversely affects the performance of the microprocessor chip, manufacturers and designers in the computer industry have responded to this heat build up problem by implementing various devices. These devices typically keep the microprocessor chip and nearby circuitry below the maximum recommended operating temperature by transferring or dissipating the heat generated by the microprocessor chip away from the chip and nearby circuitry.
For example, an electric fan is one of the earlier devices used to maintain the recommended operating temperature of the microprocessor chip. The electric fan is either placed on top of the processor to blow hot air away from the chip, or placed near the processor to blow cool air over the chip. However, there are some drawbacks to using the electric fan. First, the necessity for moving parts in these electric fans makes them unreliable. Second, the electric fans generate a significant amount of noise. Third, the use of electric fans in portable battery powered computers, where maximum battery life is desirable, is a drawback since providing power to the electric fan reduces the battery life of the computer. Fourth, the relatively large size of a typical electric fan requires a large amount of space inside the portable computer, where space is at a premium. Fifth, circulation of air into the electric fan also pulls in dust and debris.
Another device that is used to maintain the recommended operating temperature of the processor is a heat sink. Basically, the heat sink is placed in thermal communication with the processor, and comprises a thermally conductive block of metal used to transfer heat away from the processor and into the heat sink. The transferred heat is then dissipated through the surface area of the heat sink, thereby reducing the amount of heat build up in the processor. A typical heat sink comprises a plurality of protrusions, called fins, that increase the overall surface area of the heat sink, thereby providing for a more rapid and efficient dissipation of the heat transferred from the processor.
However, there are some drawbacks to using one primary heat sink, especially in portable computers that implement processors which generate a significant amount of heat, such as the Pentium Processor. First, if a significant amount of heat is generated by the processor, then a larger sized heat sink is necessary to adequately dissipate away the amount of heat that is generated. Second, larger sized heat sinks tend to weigh more, and take up more space. Therefore, since portable computer manufacturers are constantly striving to make their portable computers smaller and lighter, the use of the heat sink in a Pentium, or similar processor, based notebook-type computer is limited.
Another device used to maintain the recommended operating temperature of the microprocessor chip combines the use of a heat sink with an electric fan. One of the benefits of this combination is that a smaller heat sink can be used. Since the electric fan increases the dissipation of heat from the surface of the heat sink, a smaller heat sink with a fan can dissipate as much heat as a larger heat sink without a fan. However, the heat sink and electric fan combination remains hindered by all of the drawbacks relating to the use of the electric fan mentioned above for portable computer systems.
Recently, computer manufacturers have started using heat pipes to more efficiently, and more rapidly, transfer heat away from the processor via the heat sink. The heat pipe is used to transfer the heat away from the processor via the heat sink to an underside of a keyboard on the portable computer system for further dissipation. A typical heat pipe comprises a hollow copper tube partially filled with a fluid, such as water. In alternative embodiments, the heat pipe may be comprised of a solid heat conducting material, or be filled with various other fluids. By using the heat pipe, which transfers heat away from a microprocessor chip more rapidly than by heat sink surface area dissipation to the surrounding air alone, computer manufacturers are able to reduce the overall size of the heat sink while still providing for the same amount of heat dissipation. Therefore, it is desirable to use the heat pipe and smaller heat sink in a portable computer system, since the smaller heat sink does not add significantly to the size or weight of the portable computer system. The smaller heat sink, which would necessarily be larger without the use of the heat pipe, is placed in thermal communication with the processor, with a first end of the heat pipe affixed to the heat sink. A second end of the heat pipe is affixed to a metal panel located on the underside of the keyboard. Since the heat pipe is in a fixed position relative to the heat sink and keyboard, position tolerances are very small and extra care must be taken to ensure that these components are positioned properly in the computer system.
The use of the heat pipe in conjunction with the heat sink and keyboard reduces or eliminates many of the drawbacks associated with the fan and heat sink devices. For example, since no electric power is needed to run the heat pipe, there is no reduction in the battery life of the portable computer system. Furthermore, there is no dust or debris pulled in, no fan noise, and fan reliability problems. In addition, the heat sink can be made smaller and lighter since the heat pipe increases the ability of the smaller heat sink to transfer heat away from the processor.
However, there are some drawbacks with the way that the heat pipe is currently being used. For example, in most portable computer systems today, the processor is mounted to a printed circuit board with the heat sink attached to the processor, and the printed circuit board is typically attached to a bottom portion of a casing for the portable computer system. The keyboard is then typically attached as a lid to the casing, enclosing the printed circuit board that comprises the processor and the heat sink. Since the heat pipe is rigidly attached to the heat sink and to the underside of the keyboard during installation of the heat pipe, any attempt to remove the keyboard or to open up the portable computer system casing for maintenance, repairs, or modifications could result in a broken or bent heat pipe. In order to safely remove the keyboard or open up the casing, a user has to detach the rigidly affixed heat pipe from either the heat sink or the keyboard without breaking or bending the heat pipe.
In certain portable computer designs, the keyboard is designed to flip up or be removed so that various internal components, such as a battery, hard disk drive, or floppy disk drive can be removed, replaced, or swapped. Because of the rigid attachment of the heat pipe to the heat sink and keyboard in current heat pipe installations, a portable computer system implementing a flippable or removable keyboard design cannot take advantage of the heat dissipating benefits provided by the heat pipe, since the keyboard cannot be removed without the likelihood of damaging the heat pipe.
Therefore, a better solution is needed to provide the heat dissipating benefits of the heat pipe without the drawbacks associated with current heat pipe implementations.